[ViewVC] Diff of: cvs/Coro/Coro.pm

Comparing Coro/Coro.pm (file contents):
Revision 1.80 by root, Mon Nov 6 19:56:26 2006 UTC vs.
Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC

…		…
8		8
9	async {	9	async {
10	# some asynchronous thread of execution	10	# some asynchronous thread of execution
11	};	11	};
12		12
13	# alternatively create an async process like this:	13	# alternatively create an async coroutine like this:
14		14
15	sub some_func : Coro {	15	sub some_func : Coro {
16	# some more async code	16	# some more async code
17	}	17	}
18		18
19	cede;	19	cede;
20		20
21	=head1 DESCRIPTION	21	=head1 DESCRIPTION
22		22
23	This module collection manages coroutines. Coroutines are similar to	23	This module collection manages coroutines. Coroutines are similar
24	threads but don't run in parallel.	24	to threads but don't run in parallel at the same time even on SMP
		25	machines. The specific flavor of coroutine use din this module also
		26	guarentees you that it will not switch between coroutines unless
		27	necessary, at easily-identified points in your program, so locking and
		28	parallel access are rarely an issue, making coroutine programming much
		29	safer than threads programming.
25		30
		31	(Perl, however, does not natively support real threads but instead does a
		32	very slow and memory-intensive emulation of processes using threads. This
		33	is a performance win on Windows machines, and a loss everywhere else).
		34
26	In this module, coroutines are defined as "callchain + lexical variables	35	In this module, coroutines are defined as "callchain + lexical variables +
27	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own	36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
28	callchain, it's own set of lexicals and it's own set of perl's most	37	its own set of lexicals and its own set of perls most important global
29	important global variables.	38	variables.
30		39
31	=cut	40	=cut
32		41
33	package Coro;	42	package Coro;
34		43
35	use strict;	44	use strict;
36	no warnings "uninitialized";	45	no warnings "uninitialized";
37		46
38	use Coro::State;	47	use Coro::State;
39		48
40	use base Exporter::;	49	use base qw(Coro::State Exporter);
41		50
42	our $idle; # idle coroutine	51	our $idle; # idle handler
43	our $main; # main coroutine	52	our $main; # main coroutine
44	our $current; # current coroutine	53	our $current; # current coroutine
45		54
46	our $VERSION = '2.5';	55	our $VERSION = '3.1';
47		56
48	our @EXPORT = qw(async cede schedule terminate current);	57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);
49	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
51	);	60	);
52	our @EXPORT_OK = @{$EXPORT_TAGS{prio}};	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
53		62
54	{	63	{
55	my @async;	64	my @async;
56	my $init;	65	my $init;
57		66
58	# this way of handling attributes simply is NOT scalable ;()	67	# this way of handling attributes simply is NOT scalable ;()
59	sub import {	68	sub import {
60	no strict 'refs';	69	no strict 'refs';
61		70
62	Coro->export_to_level(1, @_);	71	Coro->export_to_level (1, @_);
63		72
64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
66	my ($package, $ref) = (shift, shift);	75	my ($package, $ref) = (shift, shift);
67	my @attrs;	76	my @attrs;
…		…
95		104
96	$main = new Coro;	105	$main = new Coro;
97		106
98	=item $current (or as function: current)	107	=item $current (or as function: current)
99		108
100	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).	109	The current coroutine (the last coroutine switched to). The initial value
		110	is C<$main> (of course).
		111
		112	This variable is B<strictly> I<read-only>. It is provided for performance
		113	reasons. If performance is not essentiel you are encouraged to use the
		114	C<Coro::current> function instead.
101		115
102	=cut	116	=cut
103		117
104	# maybe some other module used Coro::Specific before...	118	# maybe some other module used Coro::Specific before...
105	if ($current) {
106	$main->{specific} = $current->{specific};	119	$main->{specific} = $current->{specific}
107	}	120	if $current;
108		121
109	$current = $main;	122	_set_current $main;
110		123
111	sub current() { $current }	124	sub current() { $current }
112		125
113	=item $idle	126	=item $idle
114		127
115	The coroutine to switch to when no other coroutine is running. The default	128	A callback that is called whenever the scheduler finds no ready coroutines
116	implementation prints "FATAL: deadlock detected" and exits.	129	to run. The default implementation prints "FATAL: deadlock detected" and
		130	exits, because the program has no other way to continue.
117		131
118	=cut	132	This hook is overwritten by modules such as C<Coro::Timer> and
		133	C<Coro::Event> to wait on an external event that hopefully wake up a
		134	coroutine so the scheduler can run it.
119		135
120	# should be done using priorities :(	136	Please note that if your callback recursively invokes perl (e.g. for event
121	$idle = new Coro sub {	137	handlers), then it must be prepared to be called recursively.
122	print STDERR "FATAL: deadlock detected\n";	138
123	exit(51);	139	=cut
		140
		141	$idle = sub {
		142	require Carp;
		143	Carp::croak ("FATAL: deadlock detected");
124	};	144	};
125		145
126	# this coroutine is necessary because a coroutine	146	# this coroutine is necessary because a coroutine
127	# cannot destroy itself.	147	# cannot destroy itself.
128	my @destroy;	148	my @destroy;
129	my $manager;
130	$manager = new Coro sub {	149	my $manager; $manager = new Coro sub {
131	while () {	150	while () {
132	# by overwriting the state object with the manager we destroy it	151	# by overwriting the state object with the manager we destroy it
133	# while still being able to schedule this coroutine (in case it has	152	# while still being able to schedule this coroutine (in case it has
134	# been readied multiple times. this is harmless since the manager	153	# been readied multiple times. this is harmless since the manager
135	# can be called as many times as neccessary and will always	154	# can be called as many times as neccessary and will always
…		…
137	while (@destroy) {	156	while (@destroy) {
138	my $coro = pop @destroy;	157	my $coro = pop @destroy;
139	$coro->{status} \|\|= [];	158	$coro->{status} \|\|= [];
140	$_->ready for @{delete $coro->{join} \|\| []};	159	$_->ready for @{delete $coro->{join} \|\| []};
141		160
142	# the next line destroys the _coro_state, but keeps the	161	# the next line destroys the coro state, but keeps the
143	# process itself intact (we basically make it a zombie	162	# coroutine itself intact (we basically make it a zombie
144	# process that always runs the manager thread, so it's possible	163	# coroutine that always runs the manager thread, so it's possible
145	# to transfer() to this process).	164	# to transfer() to this coroutine).
146	$coro->{_coro_state} = $manager->{_coro_state};	165	$coro->_clone_state_from ($manager);
147	}	166	}
148	&schedule;	167	&schedule;
149	}	168	}
150	};	169	};
151		170
…		…
153		172
154	=back	173	=back
155		174
156	=head2 STATIC METHODS	175	=head2 STATIC METHODS
157		176
158	Static methods are actually functions that operate on the current process only.	177	Static methods are actually functions that operate on the current coroutine only.
159		178
160	=over 4	179	=over 4
161		180
162	=item async { ... } [@args...]	181	=item async { ... } [@args...]
163		182
164	Create a new asynchronous process and return it's process object	183	Create a new asynchronous coroutine and return it's coroutine object
165	(usually unused). When the sub returns the new process is automatically	184	(usually unused). When the sub returns the new coroutine is automatically
166	terminated.	185	terminated.
		186
		187	Calling C<exit> in a coroutine will not work correctly, so do not do that.
167		188
168	When the coroutine dies, the program will exit, just as in the main	189	When the coroutine dies, the program will exit, just as in the main
169	program.	190	program.
170		191
171	# create a new coroutine that just prints its arguments	192	# create a new coroutine that just prints its arguments
…		…
175		196
176	=cut	197	=cut
177		198
178	sub async(&@) {	199	sub async(&@) {
179	my $pid = new Coro @_;	200	my $pid = new Coro @_;
180	$manager->ready; # this ensures that the stack is cloned from the manager
181	$pid->ready;	201	$pid->ready;
182	$pid;	202	$pid
183	}	203	}
184		204
185	=item schedule	205	=item schedule
186		206
187	Calls the scheduler. Please note that the current process will not be put	207	Calls the scheduler. Please note that the current coroutine will not be put
188	into the ready queue, so calling this function usually means you will	208	into the ready queue, so calling this function usually means you will
189	never be called again.	209	never be called again unless something else (e.g. an event handler) calls
		210	ready.
190		211
191	=cut	212	The canonical way to wait on external events is this:
		213
		214	{
		215	# remember current coroutine
		216	my $current = $Coro::current;
		217
		218	# register a hypothetical event handler
		219	on_event_invoke sub {
		220	# wake up sleeping coroutine
		221	$current->ready;
		222	undef $current;
		223	};
		224
		225	# call schedule until event occured.
		226	# in case we are woken up for other reasons
		227	# (current still defined), loop.
		228	Coro::schedule while $current;
		229	}
192		230
193	=item cede	231	=item cede
194		232
195	"Cede" to other processes. This function puts the current process into the	233	"Cede" to other coroutines. This function puts the current coroutine into the
196	ready queue and calls C<schedule>, which has the effect of giving up the	234	ready queue and calls C<schedule>, which has the effect of giving up the
197	current "timeslice" to other coroutines of the same or higher priority.	235	current "timeslice" to other coroutines of the same or higher priority.
198		236
199	=cut
200
201	=item terminate [arg...]	237	=item terminate [arg...]
202		238
203	Terminates the current process with the given status values (see L<cancel>).	239	Terminates the current coroutine with the given status values (see L<cancel>).
204		240
205	=cut	241	=cut
206		242
207	sub terminate {	243	sub terminate {
208	$current->cancel (@_);	244	$current->cancel (@_);
…		…
210		246
211	=back	247	=back
212		248
213	# dynamic methods	249	# dynamic methods
214		250
215	=head2 PROCESS METHODS	251	=head2 COROUTINE METHODS
216		252
217	These are the methods you can call on process objects.	253	These are the methods you can call on coroutine objects.
218		254
219	=over 4	255	=over 4
220		256
221	=item new Coro \&sub [, @args...]	257	=item new Coro \&sub [, @args...]
222		258
223	Create a new process and return it. When the sub returns the process	259	Create a new coroutine and return it. When the sub returns the coroutine
224	automatically terminates as if C<terminate> with the returned values were	260	automatically terminates as if C<terminate> with the returned values were
225	called. To make the process run you must first put it into the ready queue	261	called. To make the coroutine run you must first put it into the ready queue
226	by calling the ready method.	262	by calling the ready method.
227		263
228	=cut	264	Calling C<exit> in a coroutine will not work correctly, so do not do that.
229		265
		266	=cut
		267
230	sub _newcoro {	268	sub _run_coro {
231	terminate &{+shift};	269	terminate &{+shift};
232	}	270	}
233		271
234	sub new {	272	sub new {
235	my $class = shift;	273	my $class = shift;
236	bless {
237	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
238	}, $class;
239	}
240		274
241	=item $process->ready	275	$class->SUPER::new (\&_run_coro, @_)
		276	}
242		277
243	Put the given process into the ready queue.	278	=item $success = $coroutine->ready
244		279
245	=cut	280	Put the given coroutine into the ready queue (according to it's priority)
		281	and return true. If the coroutine is already in the ready queue, do nothing
		282	and return false.
246		283
		284	=item $is_ready = $coroutine->is_ready
		285
		286	Return wether the coroutine is currently the ready queue or not,
		287
247	=item $process->cancel (arg...)	288	=item $coroutine->cancel (arg...)
248		289
249	Terminates the given process and makes it return the given arguments as	290	Terminates the given coroutine and makes it return the given arguments as
250	status (default: the empty list).	291	status (default: the empty list).
251		292
252	=cut	293	=cut
253		294
254	sub cancel {	295	sub cancel {
…		…
257	push @destroy, $self;	298	push @destroy, $self;
258	$manager->ready;	299	$manager->ready;
259	&schedule if $current == $self;	300	&schedule if $current == $self;
260	}	301	}
261		302
262	=item $process->join	303	=item $coroutine->join
263		304
264	Wait until the coroutine terminates and return any values given to the	305	Wait until the coroutine terminates and return any values given to the
265	C<terminate> or C<cancel> functions. C<join> can be called multiple times	306	C<terminate> or C<cancel> functions. C<join> can be called multiple times
266	from multiple processes.	307	from multiple coroutine.
267		308
268	=cut	309	=cut
269		310
270	sub join {	311	sub join {
271	my $self = shift;	312	my $self = shift;
…		…
274	&schedule;	315	&schedule;
275	}	316	}
276	wantarray ? @{$self->{status}} : $self->{status}[0];	317	wantarray ? @{$self->{status}} : $self->{status}[0];
277	}	318	}
278		319
279	=item $oldprio = $process->prio($newprio)	320	=item $oldprio = $coroutine->prio ($newprio)
280		321
281	Sets (or gets, if the argument is missing) the priority of the	322	Sets (or gets, if the argument is missing) the priority of the
282	process. Higher priority processes get run before lower priority	323	coroutine. Higher priority coroutines get run before lower priority
283	processes. Priorities are small signed integers (currently -4 .. +3),	324	coroutines. Priorities are small signed integers (currently -4 .. +3),
284	that you can refer to using PRIO_xxx constants (use the import tag :prio	325	that you can refer to using PRIO_xxx constants (use the import tag :prio
285	to get then):	326	to get then):
286		327
287	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN	328	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
288	3 > 1 > 0 > -1 > -3 > -4	329	3 > 1 > 0 > -1 > -3 > -4
…		…
291	current->prio(PRIO_HIGH);	332	current->prio(PRIO_HIGH);
292		333
293	The idle coroutine ($Coro::idle) always has a lower priority than any	334	The idle coroutine ($Coro::idle) always has a lower priority than any
294	existing coroutine.	335	existing coroutine.
295		336
296	Changing the priority of the current process will take effect immediately,	337	Changing the priority of the current coroutine will take effect immediately,
297	but changing the priority of processes in the ready queue (but not	338	but changing the priority of coroutines in the ready queue (but not
298	running) will only take effect after the next schedule (of that	339	running) will only take effect after the next schedule (of that
299	process). This is a bug that will be fixed in some future version.	340	coroutine). This is a bug that will be fixed in some future version.
300		341
301	=cut
302
303	sub prio {
304	my $old = $_[0]{prio};
305	$_[0]{prio} = $_[1] if @_ > 1;
306	$old;
307	}
308
309	=item $newprio = $process->nice($change)	342	=item $newprio = $coroutine->nice ($change)
310		343
311	Similar to C<prio>, but subtract the given value from the priority (i.e.	344	Similar to C<prio>, but subtract the given value from the priority (i.e.
312	higher values mean lower priority, just as in unix).	345	higher values mean lower priority, just as in unix).
313		346
314	=cut
315
316	sub nice {
317	$_[0]{prio} -= $_[1];
318	}
319
320	=item $olddesc = $process->desc($newdesc)	347	=item $olddesc = $coroutine->desc ($newdesc)
321		348
322	Sets (or gets in case the argument is missing) the description for this	349	Sets (or gets in case the argument is missing) the description for this
323	process. This is just a free-form string you can associate with a process.	350	coroutine. This is just a free-form string you can associate with a coroutine.
324		351
325	=cut	352	=cut
326		353
327	sub desc {	354	sub desc {
328	my $old = $_[0]{desc};	355	my $old = $_[0]{desc};
…		…
330	$old;	357	$old;
331	}	358	}
332		359
333	=back	360	=back
334		361
		362	=head2 GLOBAL FUNCTIONS
		363
		364	=over 4
		365
		366	=item Coro::nready
		367
		368	Returns the number of coroutines that are currently in the ready state,
		369	i.e. that can be swicthed to. The value C<0> means that the only runnable
		370	coroutine is the currently running one, so C<cede> would have no effect,
		371	and C<schedule> would cause a deadlock unless there is an idle handler
		372	that wakes up some coroutines.
		373
		374	=item unblock_sub { ... }
		375
		376	This utility function takes a BLOCK or code reference and "unblocks" it,
		377	returning the new coderef. This means that the new coderef will return
		378	immediately without blocking, returning nothing, while the original code
		379	ref will be called (with parameters) from within its own coroutine.
		380
		381	The reason this fucntion exists is that many event libraries (such as the
		382	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
		383	of thread-safety). This means you must not block within event callbacks,
		384	otherwise you might suffer from crashes or worse.
		385
		386	This function allows your callbacks to block by executing them in another
		387	coroutine where it is safe to block. One example where blocking is handy
		388	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
		389	disk.
		390
		391	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
		392	creating event callbacks that want to block.
		393
		394	=cut
		395
		396	our @unblock_pool;
		397	our @unblock_queue;
		398	our $UNBLOCK_POOL_SIZE = 2;
		399
		400	sub unblock_handler_ {
		401	while () {
		402	my ($cb, @arg) = @{ delete $Coro::current->{arg} };
		403	$cb->(@arg);
		404
		405	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
		406	push @unblock_pool, $Coro::current;
		407	schedule;
		408	}
		409	}
		410
		411	our $unblock_scheduler = async {
		412	while () {
		413	while (my $cb = pop @unblock_queue) {
		414	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);
		415	$handler->{arg} = $cb;
		416	$handler->ready;
		417	cede;
		418	}
		419
		420	schedule;
		421	}
		422	};
		423
		424	sub unblock_sub(&) {
		425	my $cb = shift;
		426
		427	sub {
		428	push @unblock_queue, [$cb, @_];
		429	$unblock_scheduler->ready;
		430	}
		431	}
		432
		433	=back
		434
335	=cut	435	=cut
336		436
337	1;	437	1;
338		438
339	=head1 BUGS/LIMITATIONS	439	=head1 BUGS/LIMITATIONS

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Comparing Coro/Coro.pm (file contents): Revision 1.80 by root, Mon Nov 6 19:56:26 2006 UTC vs. Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.80 by root, Mon Nov 6 19:56:26 2006 UTC vs.
Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC